By utilizing SEM, it provides you with a great avenue for getting the word out quickly and effectively. If you have the budget, then marketing on search engines for competitive keywords might be the right fit for you. But be prepared to pony up. Keywords can range anywhere from a few cents to upwards of $50 and more. The quality score for any term is reflective of what you can expect to pay for bidding on that keyword. The lower the competition, the lower the quality score and the lower the price.
Depending on your skill set, you could easily make a few hundred dollars or even a few extra thousand per month. And if you have some money to invest, you could easily launch into a variety of day trading activities. Those present some risks of your original capital. But if you know what you're doing and you work to hedge your bets by placing stops and limits, you could create sizable upside with lower-than-usual risks.